1. Field of the Invention
The present invention relates to a light source device for providing illumination light to an endoscope system, in particular, a medical endoscope system.
2. Description of Related Art
A light source device for use with a medical endoscope system is detachably connected to an endoscope to supply illumination light to a body cavity through a light guide. The light source device generally has a lamp unit including an electric lamp, a lamp housing in which the lamp unit is removably installed, and an outer case in which the lamp housing is fixedly encased. The outer case is provided with an access door for opening and closing an access opening of the outer case to the lamp unit for periodic and temporary replacement of lamps. Periodic replacement of lamps is made at regular time intervals for the purpose of keep the light source device supplying a stable amount of illumination light.
One of light source devices for medical endoscope systems disclosed in, for example, Japanese Unexamined Patent Publication No. 6-67097 has a case provided with double access doors, namely an outer and an inner access door, for opening and closing an access opening of the case for an access to an electric lamp located far back from the access doors. The electric lamp is mounted to a heat sink fixedly installed in the case by means of fixing knobs. The inner access door serves as an interlock door to brake or open a lighting circuit for the electric lamp when it is opened or removed from the case.
Another light source device for medical endoscope systems disclosed in, for example, Japanese Unexamined Patent Publication No. 9-327435, has a case provided with an access door for opening and closing an access opening of the case for an access to an electric lamp mounted to a heat sink. The access door serves as a switch to bring a discharge circuit for discharging static electricity of the heat sink alive when it is opened or removed. The light source device ensures safety lamp replacement works because static electricity of the heat sink are discharged whenever the access door is opened or removed.
The light source device provided with double access doors has the problem that replacement of lamps involves opening and closing the double access doors and handling the fixing knobs to detach and fix the heat sink which are quite troublesome.
Further, in the prior art light source devices described above have the problem that the operator incurs a danger upon replacing lamps immediately after the service of the light source device because the heat sink is too hot to be set aside from the case.